{"id":"AZL-99530","summary":"CVE-2026-80824 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: usbfs: fix use-after-free of usb_device in usbdev_release()\n\nusbdev_release() drops its reference to the struct usb_device before\ndraining the list of completed async URBs, but that drain path reads back\nthrough the same object: free_async() calls dec_usb_memory_use_count()\nfor any URB whose buffer came from the usbfs mmap() region, and its first\nstatement is bus_to_hcd(ps-\u003edev-\u003ebus).\n\nAfter a disconnect the usbfs reference can be the last one, in which case\nusb_put_dev() frees the device and the subsequent loop reads offset 80 of\nfreed memory and uses the result as a struct usb_hcd *, which\nhcd_buffer_free_pages() then dereferences.\n\nThis is reachable by an unprivileged process that has read/write access to\na /dev/bus/usb node: mmap() the fd, submit one URB with a buffer inside the\nmapping, wait for the device to be unplugged, then munmap() and close().\nIt reproduces on every attempt rather than being a race, because a live\nMAP_SHARED vma holds a reference on the struct file, so usbdev_release()\ncannot run until the last vma is gone and the freeing branch of\ndec_usb_memory_use_count() is always taken.\n\n  BUG: KASAN: slab-use-after-free in dec_usb_memory_use_count+0x3ae/0x410\n  Read of size 8 at addr ffff8880122ee050 by task poc/769\n  CPU: 1 UID: 1000 PID: 769 Comm: poc Tainted: G    B    6.12.94 #3\n\n  Call Trace:\n   dec_usb_memory_use_count+0x3ae/0x410\n   free_async+0x2aa/0x4f0\n   usbdev_release+0x375/0x460\n   __fput+0x3ea/0xb50\n   __x64_sys_close+0x86/0x100\n\n  Allocated by task 11:\n   usb_alloc_dev+0x55/0xd90\n   hub_event+0x2524/0x43d0\n\n  Freed by task 769:\n   kfree+0x121/0x360\n   device_release+0xd2/0x280\n   usb_put_dev+0x23/0x30\n   usbdev_release+0x2d8/0x460\n\nRelease the device reference after the drain loop instead. Nothing between\nthe two points requires it to have been dropped.","modified":"2026-09-06T05:31:44Z","published":"2026-09-04T16:18:10Z","upstream":["CVE-2026-80824"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80824"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-99530.json"}}],"schema_version":"1.9.0"}